RF coils for magnetic resonance imaging, spectroscopy, and other magnetic resonance applications have typically been based on conventional resonant and predetermined impedance transformation designs (‘tune and match’, tank circuit types) such as described in, for example, Roemer et al., “The NMR Phased Array,” Magn. Reson. Med. 16:192-225 (1990). However, the electronic decoupling of multiple coils of such tuned designs in a parallel acquisition array remains a significant engineering problem. In addition, such tuned coils (or sets of such coils) are generally unable to detect two different nuclides in one MR scanning session, and different coils may be needed due to the different Larmor frequencies associated with different static magnetic field strengths.